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  1. Material Makoto Asai (SLAC) Geant4 Tutorial Course

  2. Contents • Material definition • NIST material database Material - M.Asai (SLAC)

  3. Definition of material

  4. Definition of Materials • Different kinds of materials can be described: • isotopes <-> G4Isotope • elements <-> G4Element • molecules, compounds and mixtures <-> G4Material • Attributes associated to G4Material: • temperature, pressure, state, density • Prefer low-density material to vacuum • For hadronic processes, you have to have at least correct set of elements. You should not use "averaged material". • Single element material G4double density = 1.390*g/cm3; G4double a = 39.95*g/mole; G4Material* lAr = new G4Material("liquidArgon",z=18.,a,density); Material - M.Asai (SLAC)

  5. Material: molecule • A Molecule is made of several elements (composition by number of atoms) a = 1.01*g/mole; G4Element* elH = new G4Element("Hydrogen",symbol="H",z=1.,a); a = 16.00*g/mole; G4Element* elO = new G4Element("Oxygen",symbol="O",z=8.,a); density = 1.000*g/cm3; G4Material* H2O = new G4Material("Water",density,ncomp=2); G4int natoms; H2O->AddElement(elH, natoms=2); H2O->AddElement(elO, natoms=1); Material - M.Asai (SLAC)

  6. Material: compound • Compound: composition by fraction of mass a = 14.01*g/mole; G4Element* elN = new G4Element(name="Nitrogen",symbol="N",z= 7.,a); a = 16.00*g/mole; G4Element* elO = new G4Element(name="Oxygen",symbol="O",z= 8.,a); density = 1.290*mg/cm3; G4Material* Air = new G4Material(name="Air",density,ncomponents=2); G4double fracMass; Air->AddElement(elN, fracMass=70.0*perCent); Air->AddElement(elO, fracMass=30.0*perCent); Sum of fractions must be 100% Material - M.Asai (SLAC)

  7. Material: mixture • Composition of compound materials G4Element* elC = …; // define “carbon” element G4Material* SiO2 = …; // define “quartz” material G4Material* H2O = …; // define “water” material density = 0.200*g/cm3; G4Material* Aerog = new G4Material("Aerogel",density,ncomponents=3); Aerog->AddMaterial(SiO2,fractionmass=62.5*perCent); Aerog->AddMaterial(H2O ,fractionmass=37.4*perCent); Aerog->AddElement(elC ,fractionmass= 0.1*perCent); Material - M.Asai (SLAC)

  8. Element with user defined abundance • An element can be created according to user defined abundances • Ex. Create an enriched Uranium for nuclear power generation G4Isotope* isoU235 = new G4Isotope(“U235", iz=92, ia=235, a=235.0439242*g/mole); G4Isotope* isoU238 = new G4Isotope(“U238", iz=92, ia=238, a=238.0507847 *g/mole); G4Element* elenrichedU = new G4Element(“enriched U", symbol=“U" , ncomponents=2); elenrichedU->AddIsotope(isoU235, abundance=80.*perCent); elenrichedU->AddIsotope(isoU238, abundance=20.*perCent); G4Material* matenrichedU= new G4Material(“U for nuclearpower generation" , density= 19.050*g/cm3 , ncomponents = 1 , kStateSolid ); matenrichedU>AddElement( elenrichedU , fractionmass = 1.0 ); Material - M.Asai (SLAC)

  9. NIST Material Database in Geant4

  10. NIST material database • NIST database for materials is imported to Geant4 (http://physics.nist.gov/PhysRefData) • UI commands for material category • Guarantee the best accuracy for major parameters: • Density • Mean excitation potential • Chemical bounds • Element composition • Isotope composition Material - M.Asai (SLAC)

  11. NIST Elements and Isotopes Z A m error (%) Aeff ========================= 14 Si 22 22.03453 (22) 28.0855(3) 23 23.02552 (21) 24 24.011546 (21) 25 25.004107 (11) 26 25.992330 (3) 27 26.98670476 (17) 28 27.9769265327 (20) 92.2297 (7) 29 28.97649472 (3) 4.6832 (5) 30 29.97377022 (5) 3.0872 (5) 31 30.97536327 (7) 32 31.9741481 (23) 33 32.978001 (17) 34 33.978576 (15) 35 34.984580 (40) 36 35.98669 (11) 37 36.99300 (13) 38 37.99598 (29) 39 39.00230 (43) 40 40.00580 (54) 41 41.01270 (64) 42 42.01610 (75) • Natural isotope compositions • More than 3000 isotopes are defined Material - M.Asai (SLAC)

  12. ==================================== ### Elementary Materials from the NIST Data Base ==================================== Z Name ChFormula density(g/cm^3) I(eV) ==================================== 1 G4_H H_2 8.3748e-05 19.2 2 G4_He 0.000166322 41.8 3 G4_Li 0.534 40 4 G4_Be 1.848 63.7 5 G4_B 2.37 76 6 G4_C 2 81 7 G4_N N_2 0.0011652 82 8 G4_O O_2 0.00133151 95 9 G4_F 0.00158029 115 10 G4_Ne 0.000838505 137 11 G4_Na 0.971 149 12 G4_Mg 1.74 156 13 G4_Al 2.6989 166 14 G4_Si 2.33 173 NIST Elementary Materials H to Cf NIST Compounds HEP and Nuclear Materials Ex. liquid Ar, PbWO4 =================================== ### Compound Materials from the NIST Data Base =================================== N Name ChFormula density(g/cm^3) I(eV) =================================== 13 G4_Adipose_Tissue 0.92 63.2 1 0.119477 6 0.63724 7 0.00797 8 0.232333 11 0.0005 12 2e-05 15 0.00016 16 0.00073 17 0.00119 19 0.00032 20 2e-05 26 2e-05 30 2e-05 4 G4_Air 0.00120479 85.7 6 0.000124 7 0.755268 8 0.231781 18 0.012827 2 G4_CsI 4.51 553.1 53 0.47692 55 0.52308 NIST materials in Geant4 Material - M.Asai (SLAC)

  13. How to use • Do not need to define elements and materials by yourself. G4NistManager* manager = G4NistManager::GetPointer(); G4Element* elm = manager->FindOrBuildElement(“symb”, G4bool iso); G4Element* elm = manager->FindOrBuildElement(G4int Z, G4bool iso); G4Material* mat = manager->FindOrBuildMaterial(“name”, G4bool iso); G4Material* mat = manager->ConstructNewMaterial(“name”, const std::vector<G4int>& Z, const std::vector<G4double>& weight, G4double density, G4bool iso); G4double isotopeMass = manager->GetMass(G4int Z, G4int N); UI commands /material/nist/printElement --- print defined elements /material/nist/listMaterials --- print defined materials Material - M.Asai (SLAC)